Carbon dioxide gas is produced as a by-product in various manufacturing processes, including, but not limited to, coal-fired power plants used to generate heat to produce electricity. The carbon dioxide is typically released into the atmosphere. The release of carbon dioxide into the atmosphere has the potential to evolve into a significant environmental challenge. For example, the accumulation of carbon dioxide in the atmosphere is increasingly being linked to global climate-warming. Further, there are projections of continued warming in the absence of effectively managing and reducing the amount of carbon dioxide released into the atmosphere. It is generally desirable to sequester carbon dioxide produced during manufacturing processes in order to reduce the release of this gas into the atmosphere.
A variety of options have been proposed to reduce or minimize carbon dioxide emissions. One option is to install carbon capture and sequestration (“CCS”) systems in various power-generating facilities. CCS includes the capture, transportation and storage of carbon dioxide. The capture of carbon dioxide from flue gas generated in a power plant can be a very costly process. A typical pulverized coal power plant equipped with a monoethanolamine (“MEA”) based carbon dioxide capture process can result in an 80% increase for the cost of electricity generated as compared to the same power plant without the CCS equipment and process. The high cost of the carbon dioxide capture process is due, at least in part, to the intensive energy consumption. The energy cost of the MEA process can account for about 60% of the total CCS cost. Thus, it is believed that a reduction in energy consumption is important to the reduction of the total cost of carbon dioxide capture process. Total energy usage can consist of three components: steam extraction, compression work and auxiliary work. Compression work is the work required to compress carbon dioxide from operating pressure (e.g., about 2 atm) in a stripping column to the pipeline transportation-ready pressure (e.g., 150 atm). Auxiliary work includes, among others, the energy consumption of the circulation pump and pressure drop in absorption columns.
It is desired to provide an effective and efficient system or process that will capture the carbon dioxide from a carbon dioxide-containing gas stream, and a system or process that does not have significant capital and operational costs associated therewith.